Turbine drive mechanism for high-vacuum stills



Nov. 15, 1949 K. c. D. HICKMAN 2,438,191

TURBINE DRIVE MECHANISM FOR HIGHVACUUM STILLS Filed March 2, 1945 2Sheets-Sheet 1 KENNETH C.D.HICKMAN I N V EN TOR ATTORNEY Nov. 15;, 1949K. c. D. HICKMAN 2,488,191

TURBINE DRIVE MECHANISM FOR HIGH-VACUUM STILLS Filed March 2, 1945 2Sheets-$heet 2 --.-.-f a r" z \UND/57/LLED RES/DUE f KENNETH C.D.HICKJ\1AN DISTILLATE EH88 90 32 'INVENTOR EM 80 I Q r BY A M A TTORNEY Patented Nov. 15, 1949 TURBINE DRIVE MECHANISM FOR HIGH-VACUUM STILLSKenneth C. D. Hickman, Rochester, N. Y., as-

signor to Distillation Products, Inc., Rochester, N. Y., a corporationof Delaware Application March 2, 1945, Serial No. 580,574

4 Claims. 1

This invention relates to improved vacuum process and apparatus whereinan element is actuated while in a high vacuum.

Rotation or actuation of an element under high-vacuum conditionspresents many diflicult problems- It is known, for instance, to rotateelements by use of an electric motor, the armature being exposed to thehigh vacuum while the field is outside the evacuated receptacle, thewall of the receptacle being positioned between the armature and thefield. While this construction is satisfactory for small loads and smallsizes of apparatus, considerable trouble is experienced from heating ofthe armature under heavy duty conditions. The most practical wayhitherto available of rotating a member in a vacuum has been through theuse of a packed gland, the rotating shaft passing through the gland intothe evacuated system and being exposed on one side to the atmosphere andon the other side to the vacuum. Such an arrangement when properlymaintained works satisfactorily but occasions arise when gases leakthrough the gland and spoil the vacuum. Tightening of the gland tominimize the leakage results in overheating and undue frictional losses.

The invention has for its object to overcome the foregoing difiicultiesand to provide concurrent advantages and simplification of constructionnot obtainable by other means. Another object is to provide improvedprocess and apparatus wherein an element is rotated or otherwiseactuated in the presence of a high vacuum without leakage of theatmosphere into the vacuum. Another object is to provide an improvedcentrifugal vacuum still. Another object is to improve the state of theart. Other objects are apparent from the following description andclaims.

These and other objects are accomplished by my invention which includesvacuum apparatus and process wherein a moving element is actuated in aclosed evacuated receptacle by a driving means which is actuated by alow vapor pressure fluid, the driving means having a drive shaft andpacked gland and being associated with the closed receptacle so that itsdrive shaft and packed gland are exposed on one side of the gland to thehigh vacuum in the closed receptacle and on the other side of the glandto the low vapor pressure actuating liquid in the driving means.

In the following description I have given several of the preferredembodiments of my invention but it is to be understood that these areset forth by way of illustration" and not in limitation thereof.

In the accompanying drawings, wherein like numbers refer to like parts:Fig. 1 is a vertical section of vacuum apparatus having a rotatableelement positioned therein which is driven in accordance with theprinciples of my invention;

Fig. 2 is an elevation, partly in section, of a modification of theapparatus illustrated in Fig. 1 and showing the driving mechanismentirely positioned in the evacuated receptacle;

Fig. 3 is a verticalsection of a vacuum still having a vaporizingsurface rotated in accordance with my invention and;

Fig. 4 is a horizontal section taken on line 4-4 of Fig. 3.

Referring to Fig. 1, numeral It designates a cylindrical casing providedwith an integral bell shaped end l2. and with a removable bell shapedcover M which makes gas-tight connection with casing ill at flange 16.Numeral I8 indicates a conduitv through which the receptacle, or casingI0, is evacuated.

Numeral 2H designates a turbine driving means r positioned on shaft 22which is provided with a packed gland 24. Numeral 26 designates aconduit through which a low vapor pressure actuating liquid is deliveredto turbine 20 and numeral 28 designates a conduit through which spentactuating, low vapor pressure liquid is removed from turbine 28. Numeral39 designates an element to be actuated or rotated in the evacuatedchamber.

In operating the apparatus illustrated in Fig. l the receptacle I0 isevacuated by high vacuum pumps (not shown) connected to conduit l8.Shaft 22 and rotatable element 33 are caused to rotate by delivery of alow vapor pressure actuating liquid to conduit 26, this liquid beingsupplied under high pressure and caused to impinge against the bucketsof the turbine 20. Spent low vapor pressure actuating liquid is removedthrough conduit 28. Shaft 22 is exposed on one side to the low vaporpressure actuating liquid in turbine 20 and is, therefore", not exposedto the atmosphere. The other side of packed gland 24 is exposed to thehigh vacuum. However, since only low vapor pressure liquid is present onthe opposite side of the shaft, no leakage can take place except for thesmall amount of low vapor pressure liquid which itself acts as alubricant. It is, therefore, unnecessary to tighten gland 24 as tightlyas would be required to prevent leak-V age of gases. The low vaporpressure liquid has no harmful effect on the pressure existing in theevacuated receptacle so that leakage of small amounts of this liquid isnot particularly undesir able. If excessive leakage of liquid takesplace a suitable catchment gutter can be provided.

Referring to Fig. 2, numeral 32 designates a driving means actuated by alow vapor pressure liquid supplied thereto under relatively highpressure through conduit 26. This driving means is positioned entirelywithin the receptacle if], the drive shaft 22 passing through the packedgland 24. The operation of the apparatus of Fig. 2 is identical withthat described in connection with Fig. 1, the purpose of thisillustration being mainly to show the different positioning of thedriving means.

Referring to Figs. 3 and 4, numeral 5E1 designates a cylindrical steelcasing provided with an integral base 52 and a moveable cover 54 whichmakes gas-tight connection therewith at flange 56. Numeral 5T designatesan evacuating conduit for removing gases from the closed system which isformed by casing 50, base 52 and cover 54. Numeral 55 indicates a rigidsupport for an oil actuated gear pump 58, the drive shaft 6!} of whichpasses through packed gland 52 and supports rotatable vaporizing surface64. Numerals 66 and 68 designate annular gutters mounted upon the insidewall of casing 50, gutter 65 serving to collect condensate draining fromthe inside wall of 5 1 and gutter 68 serving to collect undistilledresidue thrown from the periphery of rotating plate 64. land '68 isrespectively withdrawn through conduits H3 and 12. Numeral I4 designatesa radiant heater provided with a reflector which serves to heatvaporizing plate 64 to distillation temperature. Gear pump 58 isactuated by a low vapor pressure liquid under high pressure which isdelivered from the exhaust side of pump 78 into conduit 88. This liquidflows through a control valve 82, thence into conduit 85 and then flowsinto gear pump 58, causing rotation of shaft 60 and vaporizing plate 53. Spent impelling liquid then flows into exhaust conduit 86, controlvalve 88 and thence into the intake 90 of pump 18.

In the equipment illustrated in Figs. 3 and 4, the low vapor pressureliquid is the distilland which is being distilled on vaporizing plate64. I his distilland is introduced at a slow rate through conduit 92 andcontrol valve 94 into the intake side 90 of pressure pump 18. Most ofthe distilland is continuously recirculated through the circuit formedby conduits 80 and -84, driving gear pump 58, conduit B6 and valve 88. Asmall part of the distilland is withdrawn from this circuit throughconduit 96, the amount being controlled by valve 98 and diaphragm valveI00. This controlled constant volume of withdrawn distilland then flowsthrough conduit I02 and is introduced into thte center depression I04 ofvaporizing plate 64. This introduced portion is then thrown bycentrifugal force in a thin film over the vaporizing plate 64. Vaporsare thus generated, pass upwardly and .are condensed on the inside wallof cover 54. The condensed liquid then flows by gravity into gutter 65and is withdrawn through conduit 70. Undistilled residue is thrown intogutter 68 and withdrawn through conduit 12, as previously explained.

The gear pump shown in Figs. 3 and 4 may be one which is ordinarily usedto pump oil under relatively high pressure. By supplying the oil to :thepump in reverse direction and under high pressure, the pump can be usedas a motor. Hydraulic motors especially designed for this purpose canalso be used. In the modification shown in Figs. 3 and 4 the distillandmay, for

Liquid collecting in gutters 56 '4 instance, be a fish liver oil. Theoil is supplied to pump 58 to cause it to be actuated and small amountsof the fish liver oil are withdrawn and continuously distilled on plate64. Vitamins contained in the fish oil are thus vaporized and arecondensed on the inside wall of 54 and are removed as a concentratthrough conduit 10. It is known to use a hot, low vapor pressure fluidto heat the vaporizing surface of a vacuum still.

See, for instance, my United States Patent 2,210,927, August 13, 1940.The heat transfer liquid in such a case can be used to actuate the drivefor the rotor before it is applied to the surface for heating. The sameexpedient may be used in connection with cooling fluids supplied to thecondensing surface; see, for instance, my patent above referred to.

An outstanding feature of the invention described herein is that leakageof gases is entirely prevented without involvin the friction lossesheretofore encountered. The low vapor pressure liquid, which may be ofany type, such as a hydrocarbon fraction, rotary pump oil, butylphthalate, etc., not only does not harm the vacuum when small amountsleak into the chamber, but also acts as an efficient lubricant. Otherfluids, such as steam, water, air, etc., will not serve as satisfactory{actuating fluids.

What I claim is:

1. Vacuum apparatus comprising in combination a rotatable elementpositioned in a closed receptacle, means for evacuating the closedreceptacle, a turbine driving means for driving the rotatable element, abody of fluid of vapor pressure comparable to the vapor pressure ofbutyl phthalate for actuating the turbine, said turbine having a driveshaft and packed gland and being associated with the closed receptacleso that its drive shaft and packed gland are exposed on one side of thepacked gland to the high vacuum in the closed receptacle and on theother side of the packed gland to :the actuating liquid in the drivingmeans and means for supplying the driving liquid under high pressure tothe turbine.

2. Vacuum apparatus comprising in combination wall means defining aclosed receptacle, means for evacuating said receptacle, rotatableevaporating means in said receptacle, turbine driving means for rotatingsaid evaporating means, and means for supplying under high pressure :tosaid turbine driving means driving liquid having a vapor pressurecomparable to the vapor pressure of butyl phthalate, said turbinedriving means comprising a turbine including a turbine drive shaft, saiddrive shaft being connected to said evaporating means, and turbinehousing means enclosing said turbine and including packed gland meansabout said shaft, said gland means being exposed on one side to vacuumin said receptacle and on the other side to drivin fluid in said housingmeans.

3. Vacuum apparatus comprising in combination wall means defining :aclosed receptacle, means for evacuating said receptacle, :a rotatableevaporator in said receptacle, turbine driving means for rotating saidevaporator, and means for supplying to said turbine driving means, underhigh pressure, driving liquid having a vapor pressure comparable to thevapor pressure of butyl phthalate, said means supplying driving liquidcomprising liquid pumping means and conduit means connecting saidpumping means with said turbine driving means, said turbine drivingmeans comprising a turbine including a turbine drive shaft, said driveshaft being connected to said evaporator, and turbine housing meansenclosin said turbine and including a packed gland about said shaftcommunicating said turbine housing means with said receptacle, saidpacked gland being exposed on one side to vacuum in said receptacle andon the other side of said gland to driving liquid in said turbinehousing means.

4. Vacuum apparatus comprising in combination wall means defining aclosed receptacle, means for evacuating said receptacle, a rotatableevaporator in said receptacle, turbine driving means positioned entirelywithin said receptacle, and means for supplying to said turbine drivingmeans, under high pressure, driving liquid having a vapor pressurecomparable to the vapor pressure of butyl phthalate, said turbinedriving means comprising a turbine including a turbine drive shaft, saiddrive shaft being connected to said evaporator, and turbine housingmeans including a packed gland about said drive shaft, said packed glandbeing exposed on .one side oi REFERENCES CITED The following referencesare of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 500,787 Williams July 4, 1893597,253 Backstrom Jan. 11, 1898 2,197,539 Hickman Apr. 16, 1940 202,313,175 Scott Mar. 9, 1943

